Fossil fuel combustion is an important source of power generation, and is responsible for supplying a major portion of the world's power needs. Unfortunately, the exhaust gases that result from burning fossil fuels, called “flue gases,” may contain many harmful and/or undesirable air pollutants, such as nitrogen oxides (NOx), sulfur oxides (SOx), carbon monoxide, carbon dioxide, hydrogen, mercury, ash, other volatile organic compounds, and heavy metals. These flue gas pollutants are a major contributor of pollutants to the atmosphere and environment.
In addition, many national and local governments have enacted environmental laws and regulations that limit and/or restrict the release of specific pollutants into the environment. In response, entities that rely upon the combustion of fossil fuels to power industrial processes, such as power production entities, have developed and implemented systems and methods for removing pollutants from flue gases. These new systems and methods add significant complexity and costs to the use (e.g., combustion) of fossil fuels in industrial settings (e.g., power production), resulting in higher prices to the consumer and the increased complexity for the producer. There is great need for improved flue gas treatment methods and systems, in order to decrease the costs and complexity of power production.
Conventional post-combustion treatment processes utilize multistage designs and/or processes, in which various additives (e.g., oxidizers, sorbents, and/or reducing agents) are separately injected into with the flue gas at different stages. Each additive (e.g., oxidizer, reducing agent, and/or absorbent) must then be thoroughly mixed with the flue gas, for example, to ensure that a particular additive is sufficiently allowed to interact with one or more pollutants (e.g., nitrogen oxides (NOx), sulfur oxides (SOx), carbon monoxide, carbon dioxide, hydrogen, mercury, ash, other volatile organic compounds, or heavy metals present within the flue gas). This multistage approach can be very complex and costly since each targeted pollutant requires its own additive. Such additives can add significantly to the cost associated with flue gas treatment. As such, there is a need to reduce the amount of such additives that are added to a flue gas to not more than is necessary for the effective removal of at least one pollutant from the flue gas and/or to improve the efficiency with which such additives are able to remove pollutants from the flue gas.